Review: How Snow Leopard will improve your Mac

Some are calling Apple's latest version of Mac OS X, Snow Leopard, little more than a service pack. From a distance, it certainly looks that way: there's no new eye candy, no big-ticket features and even the ballyhooed addition of support for Microsoft Exchange (ironically, even Windows doesn't come with it) is, well, boring.

But under its furry black and white skin, the £25 upgrade is worth it, and will reach into every corner of your Mac to speed things up. Surprisingly, Snow Leopard's biggest improvements are to your hardware. Think of it as a tune-up for your machine.

Longer lasting batteries

All of Apple's built-in software, from Safari to iPhoto, and a lot of third-party applications launch faster, run with less memory and use up fewer CPU cycles. But don't concern your pretty little heads with that. What it means is a cooler computer and therefore a less thirsty computer. The fans spin slower and juice in the battery isn't used to scorch your lap.

The difference is striking. For instance, on my MacBook, Safari would run at around 25 to 35 per cent of CPU, and spin up to around 100 per cent under stress in 10.5 Leopard. Right now, under 10.6, it's not even showing up in the Top 5 list, meaning it's idling at less than 4 per cent. This is with 12 tabs open. Make a Skype video call and the battery meter still goes down like a cheap ... well, you know, but in everyday use, you'll get extra battery time.

Bigger hard drive

Apple makes much of the reclamation of hard drive space when you install Snow Leopard, unusual in an OS upgrade on any platform. This is achieved both by installing less (printer drivers are downloaded on demand instead of loading gigabytes of them up front) and by optimising and compressing code. But this alone can't explain some people's claims of 20GB or more being freed up.

In fact, plug in any drive, not just the boot drive, and it will be bigger. How? Because Snow Leopard now reads drive sizes the way humans do, as chunks of 1000 kilobytes. Computers usually define a megabyte as 1,024 kilobytes. Not much with a small drive, but when you get up to the terabyte drives we have today, that discrepancy rises to 10 per cent, or 100 GB, as big as some whole drives.

Of course, just because 10.6 reports sizes in base ten instead of in base two doesn't mean your drive has grown – it just looks like it has.

Faster everything

The whole OS is snappier. Applications now load instantly instead of bouncing sleepily in the dock for a moment. Menus appear and disappear faster (although this is surely an interface timing trick). And when software vendors update their wares to take advantage of some new tech, slow, heavy applications should scream along.

There are two key features that allow this. Grand Central Dispatch and Open CL, which press into service parts of your Mac that normally spend a good deal of time loafing around, smoking cigarettes and catcalling girls, while the CPU does all the work. Grand Central Dispatch lets apps make use of the multicore processors in modern machines without having to write complex management code. A developer pretty much points its tasks at GCD and everything is taken care of. This speeds everything up.

Open CL does something similar for your graphics card, a device capable of astonishing speed when processing a gazillion tasks at a time. This is usually wasted on rendering graphics (of course), like using a Ferrari to drive to the corner store once a week. With Open CL, now it can be accessed for more mundane computing tasks, and promises a quantum leap in performance. Oh boy.

Tweaks

Along with these big, behind-the-curtain additions, there are plenty of little things that will make your life easier. For instance: when you plug your camera in, you want images to download automatically. Fine. But when you hook up an iPhone, you don't want Image Capture to open. Every. Single. Time. Now, you can decide how the OS handles all of your cameras: Ignore the iPhone, send DSLR pictures to Lightroom and point-and-shoot pics to iPhoto.

Or Services, the stealth hit of 10.6, which takes the dusty, cluttered old submenu item and lets it add functions to your software. For instance, you can rotate or resize a photo right there in the Finder, or in iPhoto you can right click and tell it to address an e-mail to everybody in the photo (using face-recognition), or to pull up a Google map with all their addresses shown.

Sounds like magic, huh? It is, and you can download or write your own Services in the revamped Automator.

In short, the new OS has more than £25 worth of new features, it's just that they don't stick out at first. But think about this. What are the usual reasons to upgrade a computer? Bigger hard drive, faster processor, better battery life, right? For just £25, you get all this on a DVD.